Naberezhnyi Daniil, Dementyev Petr
Physics of Supramolecular Systems and Surfaces, Faculty of Physics, Bielefeld University, Bielefeld 33615, Germany.
Phys Chem Chem Phys. 2020 May 6;22(17):9808-9814. doi: 10.1039/d0cp01233e.
Ionic liquids and nanoscale membranes are both considered as promising functional components to design next-generation gas separation technologies. Herein, we combine free-standing carbon nanomembranes (CNMs) with [bmim][Tf2N] ionic liquid having affinity to carbon dioxide, and explore molecular permeation through such a composite membrane. Gas transport measurements reveal an increase in the transmembrane flux of carbon dioxide as compared to that of bare CNMs, whereas passage of helium is found to be suppressed in accordance with the solubility constants. Upon exposure to water vapor, the behavior of the hybrid membrane appears to differ strikingly as hydrophilic properties of CNMs are camouflaged by the hydrophobic nature of the ionic liquid. Kinetic simulations are conducted to account for the change in permeation mechanism, and the results agree with the experimental data obtained. Our study confirms that molecular transport in two-dimensional membranes can be tailored by imparting chemical functionalities, but at the same time highlights practical challenges in surface modification.
离子液体和纳米级膜都被认为是设计下一代气体分离技术的有前景的功能组件。在此，我们将独立的碳纳米膜（CNMs）与对二氧化碳具有亲和力的[bmim][Tf2N]离子液体相结合，并探索通过这种复合膜的分子渗透。气体传输测量结果表明，与裸CNMs相比，二氧化碳的跨膜通量有所增加，而氦气的通过则根据溶解度常数受到抑制。暴露于水蒸气后，由于离子液体的疏水性掩盖了CNMs的亲水性，混合膜的行为似乎有显著差异。进行了动力学模拟以解释渗透机制的变化，结果与获得的实验数据一致。我们的研究证实，可以通过赋予化学功能来调整二维膜中的分子传输，但同时也突出了表面改性中的实际挑战。
